Tamron SP Auto Focus 17-50mm F/2.8 XR Di-II LD SP Aspherical (IF) Zoom Lens w...

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Product Overview

• Style: Nikon
• Set: US Version

The SP AF17-50mm F/2.8 is a lightweight, compact, fast standard zoom lens
designed exclusively for digital SLR cameras, expanding the product concept of
the popular SP AF28-75mm F/2.8 zoom lens. In addition, portrait shots are made
beautiful with the natural out-of-focus effect characteristic provided by the
fast F/2.8 aperture. Additionally, a broader photographic expression through
the use of faster shutter speeds as a result of the maximum aperture offers
enhanced photographic pleasure. The lens boasts one of the best close-up
shooting performances in the class of fast standard zoom lenses designed
exclusively for digital cameras and featuring an F/2.8 maximum aperture
throughout the entire zoom range, to ensure stress-free photographic shots at
all focal lengths and distances. Extraordinary detail at the macro level
AF17-50mm F/3.5-6.3 XR Di II Highlights Di II Lenses are designed for
exclusive use on digital cameras with smaller-size imagers and inherit all of
the benefits of our Di products. These lenses are not designed for
conventional cameras and digital cameras with image sensors larger than 24mm x
16mm. Extra Refractive Index Glass (XR) Extra Refractive Index (XR) glass can
bend light rays at steeper angles, thereby decreasing the physical length of
the lens while enhancing imaging performance by minimizing optical
aberrations. This has allowed Tamron to develop a line of shorter, smaller-
diameter, lighter lenses without sacrificing lens speed, and actually
upgrading image quality compared to older designs. XR glass is costlier than
conventional glass but it yields enhanced optical power distribution, making
possible many of the outstanding and innovative lens designs that bear the XR
designation. XR glass, with its superior light-bending power, makes it
possible to design a short-barrel lens with the same light-gathering ability
(aperture value) as a long-barrel lens—even with a smaller lens diameter. By
using this principle Tamron has been able to shorten the length of the entire
optical system and produce lighter, more compact lenses of the same speed, and
also to provide greater zoom ranges in lenses that are much more convenient to
carry by hand. Special glass for better performance and more compact lens
designs Low Dispersion (LD) Low dispersion (LD) glass elements in a lens help
reduce chromatic aberration; the tendency of light of different colors to come
to different points of focus at the image plane. Chromatic aberration reduces
the sharpness of an image, but glass with an extremely lowdispersion index,
has less of a tendency to separate (defract) a ray of light into a rainbow of
colors. This characteristic allows the lens designer to effectively compensate
for chromatic aberration at the center of the field (on axis), a particular
problem at long focal lengths (the telephoto end of the zoom range), and for
lateral chromatic aberration (towards the edges of the field) that often
occurs at short focal lengths (the wide-angle end of the zoom range.) Low
Dispersion (LD) Glass for Greater Lens Sharpness Super Performance (SP) for
Discriminating Shooters Tamron SP (Super Performance) series is a line of
ultra-high-performance lenses designed and manufactured to the exacting
specifications demanded by professionals and others who require the highest
possible image quality. In creating SP lenses Tamron’s optical designers put
their foremost priority on achieving superior performance parameters—they are
all designed to a higher standard with little regard for cost constraints. As
a result, Tamron lenses bearing the SP designation feature impressive and
innovative designs that have established an enviable reputation for excellence
among those knowledgeable photographers that demand the very best. Zoom Lock
(ZL) Another original Tamron mechanical engineering concept is the Zoom Lock
(ZL), a simple convenience feature that prevents undesired extension of the
lens barrel when carrying the camera/lens unit on a neck strap.